Demand for integrated circuits (ICs) in portable electronic applications has motivated greater levels of semiconductor device integration. Many advanced semiconductor devices in development leverage non-silicon semiconductor materials, including compound semiconductor materials (e.g., GaAs, InP, InGaAs, InAs, and III-N materials). III-N materials, as well as other materials with wurtzite crystallinity, such as, but not limited to AgI, ZnO, CdS, CdSe, α-SiC, and BN, show particular promise for high voltage and high frequency applications like power management ICs and RF power amplifiers. III-N heteroepitaxial (heterostructure) field effect transistors (HFET), such as high electron mobility transistors (HEMT) and metal oxide semiconductor (MOS) HEMT, employ a semiconductor heterostructure with one or more heterojunction, for example at an interface of a GaN semiconductor and another III-N semiconductor alloy, such as AlGaN or AlInN. GaN-based HFET devices benefit from a relatively wide bandgap (˜3.4 eV), enabling higher breakdown voltages than Si-based MOSFETs, as well as high carrier mobility. The III-N material system is also useful for photonics (e.g., LEDs), photovoltaics, and sensors, one or more of which may be useful to integrate into an electronic device platform.
Multi-chip integration approaches have been employed to integrate silicon-based devices with devices using alternative semiconductor materials. These multi-chip approaches have scaling and performance limitations. Monolithic integration of silicon-based devices (e.g., CMOS field effect transistors) with devices utilizing non-silicon material systems is a challenge in part due to a large lattice mismatch (e.g., ˜41% between GaN and Si) and a large thermal expansion coefficient mismatch (e.g., ˜116% between Si and GaN). These mismatches can result in a great number of defects in the heteroepitaxial semiconductor thin films grown over silicon substrates. Without an ability to control propagation of defects, regions of sufficiently low defect density may not available to form highly functional semiconductor devices. One technique for monolithic integration relies on thick buffer layers, for example of 3-10 microns, or more. Such thick buffers however are expensive and complicate silicon CMOS integration. Structures and techniques to manage defect propagation in non-native semiconductor material systems epitaxially formed on CMOS-compatible substrates without thick buffers are therefore advantageous.